Efficient injection and detection of out-of-plane spins via the anomalous spin Hall effect in permalloy nanowires

TL;DR

This paper introduces a new method using the anomalous spin Hall effect in permalloy nanowires for efficient electrical injection and detection of out-of-plane spins, with potential applications in spintronics devices.

Contribution

It demonstrates a novel mechanism for out-of-plane spin control via the anomalous spin Hall effect in permalloy nanowires, distinct from the conventional spin Hall effect.

Findings

Achieved up to 50% efficiency for out-of-plane spin injection/detection compared to in-plane spins.

Observed sign reversal of non-local magnon spin signals for out-of-plane spins.

Validated the mechanism in Py/YIG nanowire systems.

Abstract

We report a novel mechanism for the electrical injection and detection of out-of-plane spin accumulation via the anomalous spin Hall effect (ASHE), where the direction of the spin accumulation can be controlled by manipulating the magnetization of the ferromagnet. This mechanism is distinct from the spin Hall effect (SHE), where the spin accumulation is created along a fixed direction parallel to an interface. We demonstrate this unique property of the ASHE in nanowires made of permalloy (Py), to inject and detect out-of-plane spin accumulation in a magnetic insulator, yttrium iron garnet (YIG). We show that the efficiency for the injection/detection of out-of-plane spins can be up to 50% of that of in-plane spins. We further report the possibility to detect spin currents parallel to the Py/YIG interface for spins fully oriented in the out-of-plane direction, resulting in a sign reversal of the non-local magnon spin signal. The new mechanisms that we have demonstrated are highly relevant for spin torque devices and applications.